Shadow Convertible L4-135 2.2L SOHC VIN D FI (1992)
Throttle Body: Testing and Inspection
Minimum Air Flow Air Metering Fitting
Warning: Apply parking brake and/or block wheels before performing any engine running test with the vehicle on the ground.
Note:
Before performing minimum air flow test, make sure all accessories are off.
1.
Connect scan tool.
2.
Remove air cleaner, and plug heated air door vacuum hose.
3.
With vehicle in PARK (A/T) or NEUTRAL (M/T), START the engine and allow it to warm up until the cooling fan cycles at least once, then shut
OFF the engine.
4.
Connect a timing light and tachometer.
5.
Set basic timing to 12° BTDC ± 2°. SEE Powertrain Management/Ignition System/Adjustments.
6.
Shut OFF engine, disconnect PCV valve and attach metered orifice no. C-6457 (or equivalent 0.125 inch orifice) to intake manifold PCV nipple.
7.
START engine and allow to idle for at least one minute.
8.
Using scan tool [1], access MINIMUM AIRFLOW IDLE SPEED TEST.
^ The Idle Air Control (IAC) motor should close the bypass passage fully.
^ Idle spark advance should become fixed.
^ Idle fuel should become enriched.
^ Engine rpm will be displayed on the scan tool.
9.
Read idle rpm with tachometer, and compare to specifications below.
^ If idle rpm is within range, Minimum Air Flow is set correctly.
^ If idle rpm is not within specified range, perform Idle Air Control (IAC) motor actuation test using scan tool. SEE Powertrain Management
/Computers and Control Systems/Testing and Inspection/Procedures.
10.
Shut OFF the engine, remove metered orifice, scan tool, timing light and tachometer. Install PCV valve, air cleaner assembly and connect vacuum
hose.
Remarks:
[1] Follow scan tool manufacturer's instructions for procedures.
Odometer Reading
Idle Speed
Less than 1000 miles
700-1,300 RPM
More than 1000 miles
1,100-1,300 RPM
Note:
If vehicle passes minimum airflow test, and still exhibits idle speed problems, perform Idle Air Control (IAC) motor actuation test using scan
tool. SEE Diagnostic Charts/ No Fault Tests.
